For more than 40 years, IRRI has been both a major player and a platform for leveraging partnerships. One partnership established in 1985 with the Indian Agricultural Research Institute (ICAR) and the Wageningen University and Research Centre (WUR) were able to forge the Systems Analysis for Rice Production (SARP) project to develop and implement systems approaches in rice research. This effort led to greater understanding of weather, crop, soil, and pest interactions in rice and applications of rice models in estimating potential yields, yield gaps, optimal strategies for water and nitrogen management and agroecological zoning. It also resulted in collaboration among scientists of different disciplines using the systems approach as a common way of thinking. Building on the experiences with the systems research in SARP, IRRI, ICAR, and WUR decided in 1996 to continue their partnership to develop tools for land use analysis and planning. This 167-page joint publication of IRRI, ICAR, and WUR reports on various tools developed in these projects to help stakeholders explore options and opportunities for food production to meet the increasing demand, labor, capital, and other resources required for such production levels and their environmental impact. The illustration of the use of a decision support system for Haryan amply demonstrates that considerable progress has been made in developing new tools for ecoregional research.